Method or process of coating nitrocellulose films.



PATBNTED AUG. 20, 1907.

F. M. GossITT. I

METHOD 0R PROCESS 0F COMING NITROGELLULOSE FILM.

APPLICATION FILED DBU.11, 1906.

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UNITED sTATEs PATENT oEEroE.A

FRANKLIN M. OOSSITT, OF BINGHAMTON, NEW YORK, ASSIGNOR TO THE ANTHONY &

A SOOVILL COMPANY, OF BINGHAMTON,

NEW YORK.

METHOD OR PROCESS OF COATING NITROCELLULOSE FILMS.

Speccation of Letters Patent.

Application led December l1, 1906. Serial No. 347,273.

To all whom it may concern:

Be it known that l, FRANKLIN M. Gossr'r'r, a citizen of the United States, and a resident in the city of Binghamton, Broome county, State of New York, have in-vented a new and useful Method or Process of Coating Nitrocellulose Films, of which the following is a specification, reference being had to the accompanying drawings, in which- Figure l illustrates a side elevation of one form of apparatus or machine by which my process may be practiced; Fig. 2 illustrates an apparatus or machine of modified construction.

Y Nitrocellulose, pyroxylin or Celluloid films, as they are variously called, used in photography, are frequently coated with a solution of gelatin or equivalent material upon which the sensitized emulsion is applied.

The present invention is for a method or process for effecting such coating of nitrocellulose Elms or sheets and is as follows:

The film or sheet is preferably made by iiowing or spreading a suitably prepared nitrocellulose solution upon a suitable surface and after the film' or sheet has so far set that it has sufficient cohesion to enable it to be stripped from the support upon which it was spread or flowed, but before it has dried seasoned or hardened, in other words, while it is still green, so-called, and somewhat soft, sticky or tacky, it is stripped from the surface and the coating of gelatinous or other desired material in solution is applied to one or both of its sides. Thereafter the coated film is allowed to dry and harden, this part of the process being preferably hastened by the use of heat somewhat above normal temperature.

In the drawings, two forms of apparatus are shown, whereby the process may be beneficially practiced. These drawings, however, show the essential features of the machines only, not their details of construction,

Referring to Fig. 1, A represents a suitable frame for the apparatus, B a movable and preferably iiexible apron of suitable material, which is supported upon a roller C journaled at the front end of the machine and passing thence over a guide roller D, thence over another guide roller E and under a hopper F, which contains the nitrocellulose in solution.

G is a table beneath the apron, which supports it opposite the gate or opening in the hopper F, so that the apron may receive the nitrocellulose solution H smoothly, evenly and of uniform thickness. This fixed support for the apron likewise permits the use of a doctor blade or other spreader to further aid in the even, smooth and uniform application of the nitrocellulose solution. The apron and solution deposited thereon travel together from this point in the direction of the arrow. I is another roller around which the apron passes and by the time the nitrocellulose coating, supported and carried by the apron, has reached the roller I, it has attained such degree of cohesion that it may be stripped from the apron but is stillA green, so called, 'L'. e., somewhat soft and sticky. Consequently, at this roller I, the stripping or separation is effected, and the apron B passes upwardly over a small roller J and thence downwardly in the direction of the arrow around another roller K upon which it is wound up. Meantime the stripped film of nitrocellulose proceeds around the drum L 'and thence upwardlyover the small guide roller M and thence downwardly into a tank or trough N, which contains the gelatinous or other solution; -O is a submerging roller in the tank N, beneath which the nitrocellulose film is conducted, so that while passing downwardly and also upwardly through the solution, both sides of the film are coated. It thence passes through a series of deiiecting bars P, P, preferably made of glass, which serve to remove the excess of gelatinous or other solutionand likewise to smooth and even it upon the-lm- Q is a guide roller above the glass bars P, around which the coated film passes and thence over and under a series of rotating drums, R, R, which are suitably journaled upon the frame A as shown, and finally at the end of the machine it passes around measuring rollers, S, S, which are provided with a suitable index, as is well known in this and similar arts, and is finally wound up upon a roller T as a completed article ready for storage or use.

Patented Aug. 20(190'?.

Vol

It is desirable that both surfaces of the nitrocellulose i the submerging tank N, and during its passage around this drum, it may be subjected to a current of warm air having an articial temperature, say 150 degrees or thereabout, which temperature however is regulated as experience may require, so that the outer side of the film or sheet shall attain substantially the same degree of surface dryness as the other or heretofore exposed surface. The film is then subjected to the coating operation bythe apparatus described and to hasten its subsequent drying, I prefer to blow a current of air about the drums R, while the gradually hardening and drying coated film is slowly passing o ver them, the temperature of which current may beneficially be from 140 to 150 degrees Fahrenheit, or thereabout.

Notwithstanding the fact that the coating upon the surfaces of the lm or sheet comes in contact with the drums R soon after its application thereto, nevertheless there is no disturbance or disgurement thereof, on the contrary, the result of the contact and pressure,

since the surfaces of the drums are smooth, seems to resemble that of a calendering operation, whereby the surface of the coating is made additionally smooth and such as preferred. I have found that from 70 to 75 degrees Fahrenheit produces good results.

As is well known, the several drying drums R, R, and the rollers upon which the apron and finished product are wound up should be supplied with proper mechanical devices whereby they may be driven -at uniform speed, so that there will be no danger of rupturing either the coated or uncoated film or the apron, and in the machine illustrated in Fig. 1, I provide means whereby the roller K is driven by a slip belt and the roller C is 'provided with a friction device to prevent too ready unrolling. Likewise this last named roller has a backwinding attachment so that after the apron has been entirely unwound from it on to the roller K, thus completing one operation of the machine, it may be backwound for a repetition thereof. Instead of this, however, an'endless belt may be employed. All this is well known and does non require illustration or description. I

In Fig. 2 I show a machine in all substantial respects the same as that above described, excepting that the nitrocellulose film is in the first instance made upon a large revolving drum, such as is commonly used now for that purpose.

In the special embodiment of this form of the apparatus shown, a represents the drurn which is journaled at b in suitable bearings which in the instance shown are supported at c at the level of the floor, so that the lower arc of the drum projects into the space below. d is the reservoir or hopper containing the nitrocellulose solution which is applied through a suitable gate, with 0r without spreader or doctor blade, as preferred, upon the surface of the drum, which revolves slowly in the direction of the arrow. The film is partially dried or set upon the surface o'f the drum and is taken off in its green condition by stripping roller e and thence passes over guide roller f and thence downwardly around the drum L the same as before, and thence the film passes into the tank or trough N, containing the gelatinous or other solution and then upwardly over the deflecting bars P and over and under the drying drums R, the same as heretofore explained. In the use of this form of apparatus the air blasts and other features of the process as above described may be employed.

It will be obvious to those who are familiar with this art that many modifications may be made in the details of construction of the apparatus and its detail of operation without departing from the essentials of the invention. I therefore do not limit myself to any particular mechanism.

Having described my invention, I claim:

1. The described method of coating a nitrocellulose film i or sheet consisting in applying the coating material in solution to the sheet while the latter is in a soft and somewhat sticky condition.

2. The described method of-coating a nitrocellulose film or sheet consisting in applying the coating material in solution to the sheet during its manufacture and while it is still in semi-dry condition.

3. Av continuous prbcess of making and coating a film or sheet of nitrocellulose consisting in depositing nitro cellulose in solution upon a suitable surface, partially drying the same while on such surface, stripping the film therefrom while yet in semi-dry condition and applying the coating material in solution to the film.

4. A continuous process of making and coating a film or sheet of nitrocellulose consisting in depositing nitrocellulose in solution upon a suitable surface, stripping the film therefrom while yet in semi-dry condition, applying the coating material in solution to the lm while still in said condition and drying the same under heat and pressure.

5. A continuous process of making and coating a film or sheet of nitrocellulose consisting in depositing nitrocellulose in solution upon a suitable surface, partially drying the same while upon such surface, stripping the film therefrom, subjecting the under side of the film thus exposed to a partially drying operation, then applying to the lm before it has fully hardened the coating material in solution.

6. A continuous process of makingand coating a film or sheet of nitrocellulose consisting in depositing nitrocellulose in solution upon a suitable surface, partially drying the same while upon such surface, stripping the film therefrom, subjecting the under side of the film thus exposed to a partially drying operation, then applying to the film before it has fully hardened the coating material and drying the coating under heat and pressure.

v7. A continuous process of making and coating a film or sheet of nitrocellulose consisting in depositing nitrocellulose in solution upon a suitable surface, partially drying the same while on such surface, stripping the film therefrom while yet semi-dry, applying the coating material in solution to the film and passing the same under pressure in contact with a smooth surface and drying the same.

In testimony 'whereof I have signed my name to this lspecification in the presence of two subscribing witnesses.

FRANKLIN M. COSSITT.

Witnesses:

Gao. W. ToPLIFr, WM, B. Canvas. 

